From the nose back to about the seat it's near identical, but from there back to its broad backside it has been rebuilt to take a Lehman trike rear end.

Lehman have been in the business of doing trike conversions for years and H-D, having observed the popularity of Harley trikes, simply bought Lehman out so they incorporate trikes directly into their product line-up.

Customers benefit through not having to organise a conversion themselves, which requires jettisoning the back half of a pricey bike they've just paid for, then paying to have it re-engineered.

Just buying only the parts you want, with no delays, off the showroom floor with a full factory warranty wins hands down.

Who wants a trike? you might wonder, and what are they like to use? People who might have difficulty holding up a big bike for one.

A comfy ride with your feet always up seems attractive to injury victims, people with bad hips or knees, or others lacking size or strength.

Plus, a trike is easy to step on to and off with no risk of tipping over.

Its easily accessed compartments can swallow heaps of gear on outings.

But the main attraction seems to be that trikes are uncommon, so they define their owners as travellers doing things their own way: $50,000 worth of American engineering buys a distinctive individuality.

Supershiny surfaces all over the Tri Glide Untra Classic are so polished you can see you and the part of the countryside you're exploring reflected in chrome, in perfectly finished black paint or in buffed alloy.

But how does it go? It's a cruiser and goes like one.

It's not a sports bike or a tool for rough roads.

It will suit Harley fans who want to look cool on their gleaming steed, thundering along good roads in perfect weather.

The bike's finish smacks of finesse in black and chrome styling, a dream for someone who takes pride in polishing their mount just so.

Riding position is unusually well sheltered behind the bat-wing fairing, which accommodates clear dashboard instrumentation and a posh four-speaker stereo.

Foot boards allow a good bit of leg range.

The main riding differences over a bike are: trikes support themselves up straight when they're stopped (like a car) and still sit more or less straight up through corners - you don't lean into corners to turn.

Instead, you must deliberately steer in the direction you want to go (just like a car) and over-ride any (two-wheeler) instincts to lean in.

You have to do what initially feels wrong (to bike riders) and let the trike lean a touch out.

Once you're used to cornering by firmly pointing the bars, you can throttle harder through corners, loading up the (outer wheel) rear suspension and the rubber bites tarmac well.

The 1690cc (103-cubic inch) motor can punch out of corners.

The V-twin's sheer cubes will easily push the bike along straights through its six gears well into illegal speeds, but it really suits the sort of understressed, easy cruising Harleys are mostly designed for in their native territory: the American Highway.

Really wide, consistently smooth, well-engineered roads and Interstate journeys in good weather would be the trike's element.

My concern, here in Aotearoa, is that there's barely a road in this country like that.

For all its engineering, the trike does not suit narrow, or bumpy roads; slippery ones or metalled - let alone alone a skinny, wet, secondary gravel road with a poorly maintained surface.

As you encounter bumps, despite the best "bike" seat you could want, the motion of the rear axle's unsprung weight rocks the trike and those on it with shuddery longtitudinal twists of the frame.

The width of the machine means there's little room across a thin road to steer imprecisely, so you need to get cornering lines dead right.

On a metalled surface, the front and rear of the trike have an unfair fight for traction that the front wheel's never going to win.

You really don't want to lose that front wheel's traction, even momentarily, on a slippery thin road, especially one with a steep camber and deep drains or dropaway banks at the sides, if you get my drift.

The same goes for the patch of diesel on the wet asphalt: lose that front wheel, and what used to be your coolest best friend could quickly become a juggernaut with the laws of physics acting inexorably on its centre of mass despite your best efforts.

Slipping down a gully at 10kmh on a Triang is one thing, but half-a-tonne of metal propelled by more than 100 cubic inches is likely to be less forgiving if you get it wrong and cross the edge of the road.

To summarise: sunny days and near perfect roads mean great cruising with ample comfort and load capacity.

The rest of the time, trike owners would probably best polish and groom in the garage so the beast looks its best for the next sunny weekend adventure.

The Tri Glide has the comfiest seats I've sat in outside of four-wheeled (or lounge) interiors.

The seat soaks up the huge twin's vibrations, although the rest of the metalwork follows the irregular beat of the single-crankpin 45-degree V-twin with its (nearly) Dodge Viper-sized pistons.

You can't help but be aware of their rumpity reciprocation in the engine's distinct, irregular firing pattern.

It's what makes a Harley sound and shake all over the way it does.

It's a rock'n'roll trike with the stereo system to match.

Trike tricks

To get riders accustomed to a trike's differences the dealer has a DVD from H-D to alert you to must-know material:

• It takes arm strength to steer the trike around corners and trying to lean into a corner without steering hard will not work.

• You have to lean slightly out, not in, going around corners. If you're a motorcyclist, this is the opposite of what you have always done on a bike, and it will feel odd till you get used to it.

• The rear of the bike is wide, like a car, so you have to ride in the centre of your road lane, and be mindful of the width when parking or at a petrol station. When parking, the trike's electric reverse gear helps manoeuvre its substantial bulk.

• If you are confronted with an obstacle, like a fallen branch, loosen your hold on the handlebars to avoid shock and don't try to hurriedly steer around it. Just go straight over it.

• You must never put your feet on the ground while the trike is coming to a stop, as you would on a motorbike. If your boot sole gets traction and stops while the trike is still moving, a rear wheel will run into or over your ankle, and you really don't want that.

• The DVD tells you it is essential to unlearn some motorcycle habits and recommends taking it slowly until you've got used to it, and doing a training course.

• There are other things to consider that are not in the DVD, which admittedly targets United States buyers.

• Changes in the road's camber and bumps will twist the trike around its longitudinal axis, rolling it from side to side as the rear wheels move up and down relative to each other. Uneven and bumpy roads rock the boat.

• The twin rear wheels have generous traction and push the trike straight ahead strongly, so the single front wheel does all the steering work by deflecting the trike's nose laterally. If the front tyre skids for any reason (such as on slippery surfaces) you won't be able to steer.

• This is all pertinent information, as riding expectations and learned reactions based on four-wheeled or two-wheeled vehicle experience don't translate helpfully here.